The invention provides a beverage preparation machine comprising a brew head for receiving beverage cartridges of various heights and means for passing an aqueous medium through said beverage cartridges to form a beverage from one or more beverage ingredients contained in said cartridges. The brew head comprising a first part and a second part, the first and second parts being movable relative to one another from an open position in which said beverage cartridges can be received in the brew head and a closed position in which said beverage cartridge can be fixedly retained in a brew head space defined between the first and second parts. Wherein in use, beverage cartridges of various heights may be clamped in the brew head space between a distal end of a clamping member and the second part.